HI BC stands for ballistic coefficient , and this means how well it flys threw the air , So the higher BC number the better if flys , like an airplane .
Years ago they figured out they needed a model to base different flights of bullets ,So you will see words like G1 OR G7 , WELL G1 was the first model to base ammo from , the G1 was one inch in diameter and weighed 1 pound , so things were compared to this
Today we make more aerodynamic bullets so we needed a upgraded system so g7 came in to be the current drag model it is more of a sleek long pointed bullet , so , when you see numbers like with pellets from say .0018 to .0046 the higher number flys better so it will drop less and buck wind less ,
Slugs for airguns have much better BC I am a small bore slug shooter and they have Ballistic coefficients from say .0690 to .240 ,that I use ,
So these fly much better so they fly longer distances and drop less and they retain energy a very long way , when you are a pinker or short range hunter bc really dont matter if you know where your pellet lands at say 25 to 35 yards .
However when you shot long range with real guns then your BC is an input for caculating your shots , as to make a proper ballistic table you need to put in all kinds of information to make the shot ,
here is examples
1 . you shooting a pellet gun sighted in at 50 yards , you see a squirrel at 38 yards , just aim a whisker low and yu got him
2.you have a lapua .338 and you see a zombie coming at you and he is 2700 yards . and you sighted in at 100yd
you cant just aim like Kentucky wind-age in movies , so
1. you check inputs like temperature of air , you ranged zombie 2700 yds
2 you input you barometric pressure
3 alltitude
4spin drift
5,wind
6 ammo temp on real guns as powder higher temp makes more fps
7.direction of zombie
8. angle of shot
9. corolis
9 you will need you basic ballistic dope sheet to input everything so you know basic poi ,
10. you dial or hold and then you take shot on wind call last holding
11.lead if target is moving
so with all data you get your final dope for shot , their is alot of math and such small miscalculation can miss by many feet at long ranges , and also , when shooting say point blank with pcp or gun you can be off with distances and still make a good hit when you reach out ,the angle of the slug is on such an angle that you can miss by mis ranging target from 2700 to , and you input say 2780 , you just shot over the target 6 feet ,
and say same senaro target is at 180 yards and you range 100 , , and you shot , you would of killed zombie as bullet at this point is not at a huge angle descending to earth .
so I am trying to say this is what it means and how it works and what you would use it for
hope it helps
LOU